Monday, May 12, 2014

Every year, the Physics Central crew, our friends and colleagues, and thousands of students descend on Six Flags America for a day of physics thrills. During the most recent Six Flags Physics Day on May 2, we gave out accelerometers to attending students so that they could measure the g-forces they felt on the park's various coasters.

When students were done measuring their g-forces, we compiled their data and printed out charts of their altitude and acceleration throughout the ride. As our data show, the rides at Six Flags America live up to their threatening names such as "Apocalypse" and "Tower of Doom."

We measured accelerations upwards of three to four g's on some curves — that's three to four times the acceleration felt due to Earth's gravitational pull at the surface. On some of the rides' steep drops, however, our riders felt almost zero g's as they approached free fall.

But even if you didn't come to Six Flags Physics Day, you can still participate in the fun. We've compiled front-seat videos for all of the rides we measured at Six Flags America (courtesy of CoasterForce) along with acceleration data for each one.

With videos and data in hand, it's time to test your knowledge of roller coaster physics. For today's quiz, see if you can match the rides with their acceleration data.

Are you up to the challenge? Hold onto your chair, and enjoy the ride.

Ride Videos

Superman: Ride of Steel

The Superman ride is built for speed with some of the steepest drops in the whole park. While there's not as many twists and turns as the other rides, Superman more than makes up for it with near-free-fall moments during its quick descents.

Apocalypse

Apocalypse features a slew of twists, turns, and drops as it snakes around itself for a thoroughly heart-pulsing ride.

Joker's Jinx

Take some Dramamine before this one. At the very beginning, riders are launched to 60 miles per hour in under three seconds before undergoing a number of stomach-churning twits and corkscrews.

Tower of Doom

Unlike the roller coasters, the Tower of Doom only moves along one axis — up and down. Nonetheless, the quick drop from this tower will surely leave you feeling butterflies in your stomach.

Ride Data

Now that you've experienced the four rides, can you match your experience with the correct chart? Each acceleration and altitude chart below matches with either Superman, Joker's Jinx, Tower of Doom, or Apocalypse.

For each graph, the x-axis measures time and the y-axis measures both altitude and g-forces. Counterintuitively, g-forces aren't actual forces, however; instead, they are a measure of acceleration.

When you're resting on the ground, the ground pushes back against your feet with an equal and opposite force of the gravity pulling you downward. The 1-g you feel when standing still stems from the ground resisting your body's inclination to fall toward the center of the Earth. If the ground fell out from under you (and there was no air to resist your fall), you'd quickly feel zero-g's and enter a free fall toward the center of the Earth.

Keep in mind that the acceleration seen below is the magnitude of the total acceleration in all directions. Consequently, some of the highest accelerations will happen whenever there's a quick change in direction such as during helices, rapid climbs, loops, and corkscrews. This also means that high accelerations don't necessarily correspond with large changes in altitude.

Good luck!

Ride #1:

Ride #2

Ride #3

Ride #4

Answers

Highlight the invisible text to the right to see the answers: #1 = Joker's Jinx, #2 = Tower of Doom, #3 = Superman, #4 = Apocalypse